Circuit-protector.



Patented Dec. 4, I900.

A. STROMBERG.

CIRCUIT PROTECTOR.

(Application filed June 28, 1900.;

(No Model.)

H. I. fi.

UNITED STATES PATENT @rrrcn.

ALFRED STROMBERG, OF CHICAGO, ILLINOIS.

ClRCUlT-PRQTECTGR.

SPECIFICATION forming part of Letters Patent No. 662,987, dated December 4, 1900.

Application filed June 28, 1900. Serial No, 21,878. llo modem To all whom) it may concern.-

Be it known that I, ALFRED STROMBERG, a citizen of the United States, residing at Chicage, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Circuit-Protectors, (Case No. 9,) of which the following is a full, clear, concise, and exact description, reference being bad to the accompanying drawings, forming a part of this specification.

My invention relates to devices for protecting circuits against abnormal current, and has for its object the provision'of an improved safety appliance that is capable of acting as a lightning-arrester and at the same time is capable of effecting the rupture of the protected circuit upon the flow of an abnormally large current.

In the preferred embodiment of my inven tion I include a fuse under tension in the protected circuit and associate agrounded plate or terminal with the fuse in position to conduct discharges from the fuse to ground. In the preferred embodiment of the invention a grounded carbon plate is employed partially faced with insulating material, preferably of mica, which serves to permit the fuse to lie very close to the carbon plate without having actual contact therewith. I preferably main tain the fuse under tension through the agency of a spring which preferably is also capable of controlling the continuity of an alarn'l-circ uit that may be associated with the protected circuit to indicate when the fuse is ruptured.

I will explain my invention more fully by reference to theaccompanying drawings,illustrating the preferred embodiment thereof, in which Figure 1 is a diagrammatic view of a telephone-line with the protective device of my invention associated therewith. Fig. 2 is a longitudinal sectional View of the device as seen on line 2 2 of Fig. 1.

Like parts are indicated by similar characters of reference in the views.

I have shown in Fig. 1 a telephone-line extending between a substation and an exchange. Atthe substation a well-known subscribers apparatus isillustrated, comprising in this instance a switch-hook at, having a normal contact constituting a terminal of a branch, including a call-bell b and a signaling-generatorc, and an alternate contact constituting a terminal of a branch, including a telephone (Z. The telephone-line illustrated is a metallic-circuit line extending by its limbs e e to the exchange, these limbs terminating in this instance in postsf'f. These posts are preferably provided with clip springs g g, fuse-wires 72. 7t being adapted for engagement between the clips and posts. The remaining ends of the fnsewires may be knotted or twisted, as indicated, and inserted between the fingers t' z' and the terminal springs 7c 70, which serve to maintain the fuses 7t h under tension. The terminal springs lead to the springs Z l and a line-jack of any suitable construction provided for the purpose of connecting subscribers telephone-lines together for conversation. A line-indicatorm is in this instance connected between the linesprings and is also in series with the fuses h h. Springs 1'1. 91, which constitute multipled terminals of a local-alarm circuit, including a battery 0 and a bell p, are associated with the springs 7t 7t. Either spring 7; upon the rupture of the fuse held under tension thereby is adapted to press the terminal spring 12., associated therewith, against a terminal strip q, constituting the remaining terminal of the local-alarm circuit to close the said circuit.

By means of my invention I am enabled to employ the fuses h h in an additional capacity, each a terminal of alightning-arrester circuit immediately adjacent to, but out of contact with, the grounded terminal 0 of the lightning-arrester. This grounded terminal has its side or surface that is opposed to the fuses partially faced with insulating material, strips .5, preferably of mica, extending transversely across the terminal plate, which permit the fuse-wires to approach the carbon block 1' very closely. By maintaining the fuses it h under tension the portions thereof intervening between the strips of mica or other insulating material are prevented from sagging into contact with the terminal r. By being under tension the ends of the fuses may also be extended below the upper face of the plate 9 to secure as close an approach to the said plate as its facing of insulating material will permit. I find that when carbon is employed as the material of which the terminal r is composed a very effective light ning-arrester maybe produced that will permit of the repeated use of said terminal, as upon the formation of arcs the carbon will not be blistered, as in the case of metal, but will be changed at the point of arcing to powder, which may be readily brushed away.

It is obvious that changes may readily be made in the device of my invention herein shown and particularly described, and I do not therefore wish to be limited to the precise disclosure of the invention herein set forth; but,

Having thus described my invention, 1 claim as new and desire to secure by Letters Patent- 1. The combination with. a fuse for inclu sion in the circuit to be protected thereby, of a grounded lightning-arrester terminal opposed to the said fuse which constitutes a second lightnin g-arrester terminal, the grounded terminal having its surface that is opposed to the fuse partially faced with insulating material, and means for maintaining the fuse under tension, substantially as described.

2. The combination with a fuse for inclu sion in the circuit to be protected thereby, of a grounded lightning-arrester terminal composed of carbon opposed to the said fuse which constitutes a second lightning-arrester terminal, the grounded terminal having its surface that is opposed to the fuse partially faced with insulating material, and means for maintaining the fuse under tension, substantially as described.

3. The combination with a fuse for inclusion in a protected circuit, of a spring 7tfor maintaining the same under tension, an alarm-circuit, a signal device included in said alarm-circuit, and a spring 02 constituting one terminal of said alarm-circuit, a contact q constituting the remaining terminal of the said alarm-circuit and normally out of contact with the contact-spring n, the spring 7t serving upon the rupture of the fuse held under tension thereby to engage the spring n with the terminal q to close the said alarm circuit, substantially as described.

t. The combination with a fuse for inclusion in the circuit to be protected thereby,

of a grounded lightning-arrester terminal opposed to the said fuse, which fuse constitutes the second lightning-arrester terminal, the surface of the grounded lightning arrester terminal that is opposed to the fuse being partially faced with insulating material to prevent the fuse from coming in contact with the grounded lightning-arrester terminal, substantially as described.

5. The combination with a fuse for inclusion in the circuit to be protected thereby, of a grounded lightning-arrester terminal composed of carbon opposed to the said fuse, which fuse constitutes the second lightningarrester terminal,the surface of the grounded lightning-arrestcr terminal that is opposed to the fuse being partially faced with insulating material to prevent the fuse from coming in contact with the grounded lightning-arrester terminal, substantially as described.

6. The combination with a fuse for inclusion in the circuit to be protected thereby, of a grounded lightning-arrester terminal opposed to the said fuse which constitutes a second lightning-arrester terminal, the grounded terminal having its surface that is opposed to the fuse partially faced with insulating material that is in engagement with the fuse and terminal, and means for stretching the fuse across the grounded terminal and pressing the same against the insulating material and grounded terminal, whereby the fuse is placed close to the grounded terminal but maintained out of contact therewith, substantially as described.

In witness whereof I hereunto subscribe my name this 25th day of June, A. D. 1900.

ALFRED STROMBERG.

Witnesses:

Gnonen L. Canoe, HARVEY L. Hanson. 

